Q&A for How to Calculate the Circumference of a Circle

The perimeter of a circle is the same as its circumference, the distance around it. The term "perimeter" refers to the distance around any closed shape, and “circumference” applies specifically to a circle or arc.

The diameter is the length of a straight line drawn through the center of a circle from one side to the other. The circumference is the length all the way around the outside of the circle.

Circumference is the distance around the perimeter of a circle. It is calculated by multiplying the distance across the center (diameter) by Pi (3.1416).

Double the radius to get the diameter. Then multiply by pi to get the circumference.

The circumference = π x the diameter of the circle (Pi multiplied by the diameter of the circle). Simply divide the circumference by π and you will have the length of the diameter. The diameter is just the radius times two, so divide the diameter by two and you will have the radius of the circle!

Circumference (C) = pi * diameter(d). To get the diameter of a circle take the circumference (C) and divide it by pi (3.14).

Divide the circumference by pi. That's the diameter. Divide by 2. That's the radius. Square the radius, and multiply by pi. That's the area.

The diameter is twice the radius. The circumference is diameter x pi, or 2 x radius x pi.

If your radius is a mixed number, turn the number into an improper fraction. To do this, simply multiply the whole number part by the denominator and add that number to the numerator. The denominator should remain the same throughout the process. You can then use the improper fraction in your formula.

The answer depends on your number. For example, pie or 3.14 is multiplied with your number which is the diameter or radius.

This article tells us the perimeter (also called "circumference" when talking about a full circle) of a full circle is given by 2*pi*r. Since we need the perimeter of a semicircle instead of a full circle, divide this by 2 (since the arc length is half) but then add the diameter, which is two times the radius (to account for the straight part across the bottom). So, perimeter of semicircle = (2*pi*r)/2 + 2r = (2 + pi)r. Use algebra to solve for r = perimeter / (2 + pi), and you have your radius!

Because the equation to find area is pi * r^2, the first step is to divide by pi or 3.14. Then you have to find the square root of the remaining number. The answer should be your radius. Now just fill in that number for r in the circumference equation to get the final answer.

Take the area, divide by pi, take the square root of that answer. Now multiply that by 2pi and you have the circumference. Equation: Area (a) = πr^2, and circumference (c) = 2πr. So c = sqrt(a/π)*2π.

In ancient times it was discovered that the circumference of any circle can be found by multiplying its diameter by the number represented by pi.

You write out CArd as follows: C=pie d; A=pie r 2; r= radius; d=diameter. Pie X radius X radius will give you your answer.

First you would have to know the dimensions of both figures. Then you would find the area of the circle (πr²), and subtract from that the area of the rectangle (length multiplied by width).

A circle consists of 360°.

It's pi times the diameter, divided by 3.

Divide the circumference by pi or 3.14 and then divide what you got by 2.

Take half the diameter. Square it. Multiply by pi. Then multiply by the length.

If you want to convert an area measured in square inches to square feet, divide by 144. If you want to convert a volume measured in cubic inches to cubic feet, divide by 1,728.

Because the circumference of any circle is directly proportional to its diameter, the ratio of the circumferences of these two circles is the same as the ratio of their diameters.

Double the radius, then multiply by pi.

First put in the first number you are using. Then add a plus, minus, division sign, or multiplication sign. For example, if you wanted to add 36 with 51, you would put on the paper, 36+51=? Then instead of the "?" you put in the answer to the equation.

You would have to know what portion of the circumference is represented by the arc. It would help to know the arc's central angle.

Divide the circumference by pi. That's the diameter. Divide by two. That's the radius. Square the radius, and multiply by pi. That's the area of the end of the tin. Multiply by the height and that gives you the volume.

20" in diameter is a 10" radius. The area of the circle is pi*(R^2), where R is the radius. The circle has an area of 315 sq. inches. Assuming the case covers top and bottom and all around, you will need 2 circles, meaning 630 sq. in. For the sides, the fabric needed is the circumference times the height. Circumference is 2*pi*R, or 63 inches. Height is 24, so the area for the sides is 1512 sq. inches. The total fabric necessary is 2142 sq. inches, or about 15 sq. feet.

The area of a circle is given by the formula A = π r2, where A is the area and r is the radius. The circumference of a circle is C = 2 π r. If we "solve for r" in the second equation, we have r = C / (2 π ). Now we use this to replace r in the first equation: A = π [ C / (2 π ) ]2.

Divide the diameter by 2, square that number, and multiply by pi.

First, divide the circumference by pi and you will get the diameter. Divide this number by two to get the radius.